JPH1192408A - Catalyst for trimerizing ethylene and trimerization of ethylene in presence of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject catalyst for efficiently and highly selectively producing 1-hexene useful as a raw material comonomer for linear low density polyethylene from ethylene by including a chromium compound, an alkyl metal compound and a specific electron donor. SOLUTION: This catalyst comprises a neutral ligand or anionic sulfur ligand- containing chromium compound of the formula: CrAm [(m) is an integer of 1-6; A is carbon monoxide or the like), an alkyl compound of the formula: Rp MXq [0<(p)<=3, 0<=(q)<3, (p)+(q) is 1 to 3; M is lithium or the like; R is a 1-10C alkyl; X is H or the like), and one or more kinds of electron donors selected from ether compounds, ester compounds, imine compounds, isonitrile compounds, phosphine compounds, phosphine oxide compounds and phosphite compounds, and, if necessary, an aluminoxane having a hydrolysis ratio of <=0.7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ethylene trimerization catalyst and a method for trimerizing ethylene using the same.
More specifically, linear low density polyethylene (LLDP)
The present invention relates to an ethylene trimerization catalyst which can efficiently and highly selectively obtain 1-hexene useful as a raw material comonomer of E), and which is easy in catalyst preparation operation and handling, and a method for ethylene trimerization using the same. .

[0002]

2. Description of the Related Art It is known to use a chromium compound as a catalyst in a process for obtaining 1-hexene by trimerizing ethylene. For example, JP-A-62-265237 discloses a chromium compound, a polyhydrocarbyl aluminum oxide having a hydrolysis ratio of 0.8 to 1.1 (hereinafter referred to as aluminoxane) and a donor compound such as an ether compound, an amine compound or an isonitrile compound. Ligand-based catalyst systems are disclosed. JP-A-6-239920 discloses a catalyst system comprising a chromium compound, a pyrrole-containing compound, a metal alkyl and a halide.
No. 0692 discloses a catalyst system comprising a reaction product of a chromium salt and a metal amide, a solid inorganic oxide, an aluminoxane and an electron donor compound.

[0003]

In the ethylene trimerization method using a chromium compound as a catalyst, it is necessary to treat a waste chromium catalyst at the end of the ethylene trimerization reaction, but the chromium compound constituting the catalyst depends on the structure. Produces extremely toxic compounds. Therefore, from the aspect of safety,
Although it is necessary to minimize the amount of chromium metal used, the method described in JP-A-62-265237 has a problem that the activity per chromium is not sufficient and a large amount of chromium compound must be used. Was. In order to exhibit catalytic activity, it is essential to use an aluminoxane having a hydrolysis ratio of 0.8 to 1.1 as one of the catalyst components. However, although aluminoxane is obtained by the reaction between an alkyl aluminum compound and water in a hydrocarbon solvent, when the hydrolysis ratio is controlled to 0.8 to 1.2, a certain amount of heterogeneous precipitate is easily obtained. It was difficult to obtain an aluminoxane having physical properties, and therefore, there was a problem in reproducibility of the catalyst, such as lack of reproducibility of the catalyst activity, and poor storage stability due to instability of aluminoxane.

Further, the method described in JP-A-6-239920 improves the activity per chromium and suppresses the amount of the chromium compound used. However, in this method, the catalyst preparation operation is complicated, and the pyrrole-containing compound, which is one component of the catalyst, is extremely unstable to air, so it is easily colored and deteriorated. However, it was not enough as an industrial catalyst. Also,
In the method described in JP-A-9-20692, an inorganic oxide solid is indispensable as one component of the catalyst, so that the catalyst preparation operation such as calcining and drying the inorganic oxide solid becomes complicated, Has a problem that it is difficult to handle the catalyst solution and to introduce the catalyst into the reactor because the slurry solution is used.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an industrially advantageous catalyst system which is easy in catalyst preparation operation and handling, and which is useful as a raw material comonomer of LLDPE. An object of the present invention is to provide a method for trimerizing ethylene, which can efficiently and highly selectively obtain hexene from ethylene.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a catalyst comprising a chromium compound, an alkyl metal compound and a specific electron donor has been prepared and used in the preparation and handling of the catalyst. It has been found that when the ethylene trimerization reaction is carried out in the presence of this catalyst, very high catalytic activity and high selectivity are exhibited, and the present invention has been completed. That is, the present invention comprises one or more electron donors selected from the group consisting of chromium compounds, alkyl metal compounds and ether compounds, ester compounds, imine compounds, isonitrile compounds, phosphine compounds, phosphine oxide compounds and phosphite compounds. The present invention relates to an ethylene trimerization catalyst and a method for trimerizing ethylene using the catalyst.

[0007]

Next, the present invention will be described in more detail.

In the present invention, a chromium compound is used. The chromium compound is not particularly limited. For example, the following general formula (1) CrA _m (1) (where m is an integer of 1 to 6. A is carbon monoxide, arene, Alkene, alkyne, nitrogen, isonitrile, phosphine, phosphite, sulfide, sulfoxide, thiocarboxylate group, dithiocarboxylate group, and thioalkoxy group. Chromium compounds containing co- or anionic sulfur ligands are preferably used.

In the above general formula (1), the arene is not particularly limited. For example, benzene, toluene, ethylbenzene, isopropylbenzene, t-butylbenzene, xylene, diisopropylbenzene, dibutylbenzene, trimethylbenzene, Tetramethylbenzene, hexamethylbenzene, triphenylbenzene, methyl benzoate, ethyl benzoate, dimethyl terephthalate, fluorobenzene, anisole, ethyl phenylacetate, styrene, phenylacetylene, trimethylsilylbenzene, triethoxysilylbenzene,
Trimethylgermaniumbenzene, trimethylstannylbenzene, triphenylborane, triphenylphosphine, phenylmethylsulfide, biphenyl, diphenylethane, diphenylpropane, diphenylbutane, diphenylethylene, diphenylbutadiene, naphthalene, tetrahydronaphthalene, dihydronaphthalene, acenaphthylene, anthracene, Dihydroanthracene,
Phenanthrene, dihydrophenanthrene, indane,
Examples include indene, fluorene, pyrene, benzothiophene, furan or thiophene. Further, a polymer containing an aromatic compound as an arene is also included.

The alkene is not particularly restricted but includes, for example, ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, butadiene, isoprene, octadiene, Examples thereof include cyclooctadiene, octatriene, cyclooctatriene, and cycloheptatriene. Alkyne is not particularly limited,
For example, acetylene, phenylacetylene, diphenylacetylene, acetylenedicarboxylic acid diethyl ester and the like can be mentioned. Although it does not specifically limit as isonitrile, For example, cyclohexyl isonitrile, t-butyl isonitrile, etc. are mentioned. Although it does not specifically limit as a phosphine, For example,
Examples include trimethylphosphine, triethylphosphine, tributylphosphine, tricyclohexylphosphine, trifluorophosphine, triphenylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, and dimethylphosphinoethane. Although it does not specifically limit as a phosphite, For example,
Examples thereof include trimethyl phosphite, tributyl phosphite, and triphenyl phosphite. Although it does not specifically limit as a sulfide, For example, dimethyl sulfide, diethyl sulfide, dibutyl sulfide, diphenyl sulfide, tetramethylene sulfide, phenylmethyl sulfide, etc. are mentioned. Although it does not specifically limit as a sulfoxide, For example, dimethyl sulfoxide, tetramethylene sulfoxide, diphenyl sulfoxide, etc. are mentioned. Although it does not specifically limit as a thiocarboxylate group, For example, a thioacetate group or a thiobenzoate group is mentioned. As the dithiocarboxylate group,
Although not particularly limited, for example, a dithioacetate group or a dithiobenzoate group may be mentioned. Although it does not specifically limit as a thioalkoxy group, For example, a thiomethoxy group, a thioethoxy group, a thiobutoxy group, a thiophenoxy group, etc. are mentioned.

The chromium compound represented by the above general formula (1) is not particularly limited. For example, hexacarbonyl chromium (0), pentacarbonyl (triphenylphosphine) chromium (0), tetracarbonyl bis ( Ethylene) chromium (0), tricarbonyl (benzene) chromium (0), tricarbonyl (toluene) chromium (0), tricarbonyl (ethylbenzene) chromium (0), tricarbonyl (isopropylbenzene) chromium (0), tricarbonyl (T-butylbenzene) chromium (0), tricarbonyl (xylene) chromium (0),
Tricarbonyl (diisopropylbenzene) chromium (0), tricarbonyl (dibutylbenzene) chromium (0), tricarbonyl (trimethylbenzene) chromium (0), tricarbonyl (tetramethylbenzene) chromium (0), tricarbonyl (hexamethyl) Benzene) chromium (0), tricarbonyl (triphenylbenzene)
Chromium (0), tricarbonyl (styrene) chromium (0), tricarbonyl (phenylacetylene) chromium (0), tricarbonyl (trimethylsilylbenzene)
Chromium (0), tricarbonyl (triethoxysilylbenzene) chromium (0), tricarbonyl (trimethylgermanium benzene) chromium (0), tricarbonyl (trimethylstannylbenzene) chromium (0), tricarbonyl [1,4- Bis (tributylstannyl) benzene] chromium (0), tricarbonyl (triphenylborane) chromium (0), tricarbonyl (triphenylphosphine) chromium (0), tricarbonyl (phenylmethylsulfide) chromium (0), tricarbonyl Carbonyl (biphenyl) chromium (0), tricarbonyl (diphenylethane) chromium (0), tricarbonyl (diphenylpropane) chromium (0), tricarbonyl (diphenylbutane) chromium (0), tricarbonyl (diphenylethylene) chromium ( 0), g Carbonyl (diphenylbutadiene) chromium (0), tricarbonyl (naphthalene) chromium (0), tricarbonyl (tetrahydronaphthalene) chromium (0), tricarbonyl (dihydronaphthalene) chromium (0), tricarbonyl (acenaphthylene)
Chromium (0), tricarbonyl (anthracene) chromium (0), tricarbonyl (dihydroanthracene) chromium (0), tricarbonyl (phenanthrene) chromium (0), tricarbonyl (dihydrophenanthrene) chromium (0), tricarbonyl Carbonyl (indane) chromium (0), tricarbonyl (indene) chromium (0), tricarbonyl (fluorene) chromium (0), tricarbonyl (pyrene) chromium (0), tricarbonyl (benzothiophene) chromium (0), Tricarbonyl (thiophene) chromium (0), tricarbonyl (cycloheptatriene) chromium (0), tricarbonyltris (t-butylisonitrile) chromium (0), tricarbonyltris (triphenylphosphite) chromium (0), (Ethylene) dicarbonyl (hexa) (Tylbenzene) chromium (0), (ethylene) dicarbonyl (trimethylbenzene) chromium (0), (ethylene) dicarbonyl (benzene) chromium (0), (ethylene) dicarbonyl (naphthalene) chromium (0), (propylene) Dicarbonyl (hexamethylbenzene) chromium (0), (butene) dicarbonyl (trimethylbenzene) chromium (0), (pentene) dicarbonyl (hexamethylbenzene) chromium (0), (hexene) dicarbonyl (trimethylbenzene) Chromium (0), (heptene) dicarbonyl (trimethylbenzene) chromium (0), (octene) dicarbonyl (trimethylbenzene) chromium (0), (nonene) dicarbonyl (benzene) chromium (0), (decene) di Carbonyl (trimethylbenzene) chromium (0), Lopenten) dicarbonyl (hexamethylbenzene) chromium (0), (cyclohexene) dicarbonyl (benzene) chromium (0), (cycloheptene) dicarbonyl (hexamethylbenzene) chromium (0), (cyclooctene) dicarbonyl (trimethyl) Benzene) chromium (0), (butadiene) dicarbonyl (hexamethylbenzene) chromium (0), (isoprene) dicarbonyl (trimethylbenzene) chromium (0), (octadiene) dicarbonyl (hexamethylbenzene) chromium (0) (Cyclooctadiene) dicarbonyl (trimethylbenzene) chromium (0), (octatriene) dicarbonyl (trimethylbenzene) chromium (0), (cyclooctatriene) dicarbonyl (trimethylbenzene) chromium (0), (acetylene ) Dicarbonyl (hexamethylbenzene) chromium (0), (phenylacetylene) dicarbonyl (trimethylbenzene) chromium (0), (diphenylacetylene) dicarbonyl (hexamethylbenzene) chromium (0), benzonitrile dicarbonyl (benzene) Chromium (0), cyclohexylisonitriledicarbonyl (benzene) chromium (0), triphenylphosphinedicarbonyl (trimethylbenzene) chromium (0), trimethylphosphinedicarbonyl (trimethylbenzene) chromium (0), triethylphosphinedicarbonyl (benzene) ) Chromium (0), tributylphosphinedicarbonyl (trimethylbenzene) chromium (0), tricyclohexylphosphinedicarbonyl (trimethylbenzene) chromium (0), trifluorophosphine Dicarbonyl (trimethylbenzene) chromium (0), diphenylmethylphosphinedicarbonyl (hexamethylbenzene) chromium (0), methyldiphenylphosphinedicarbonyl (hexamethylbenzene) chromium (0), dimethylphosphinoethanedicarbonyl (trimethyl Benzene) chromium (0), trimethyl phosphite dicarbonyl (hexamethylbenzene) chromium (0), triphenyl phosphite dicarbonyl (hexamethylbenzene) chromium (0), tetramethylene sulfide dicarbonyl (hexamethylbenzene) chromium ( 0), dimethylsulfoxidedicarbonyl (hexamethylbenzene) chromium (0), tetramethylenesulfoxidedicarbonyl (benzene) chromium (0), diphenylsulfoxidedicarbonyl Benzene) chromium (0), [triphenylphosphinedicarbonylchromium (0)] dimer, bis (benzene) chromium (0), bis (ethylbenzene) chromium (0), bis (hexamethylbenzene) chromium (0), etc. No.

Further, chromium (II) tris (thioacetate), chromium (II) tris (thiobenzoate),
Chromium (II) tris (2-ethylthiohexanoate), chromium (III) tris (thioacetate), chromium (III) tris (thiobenzoate), chromium (III) tris (2-ethylthiohexanoate),
Chromium (II) tris (dithioacetate), chromium (II) tris (dithiobenzoate), chromium (I
I) tris (2-ethyldithiohexanoate), chromium (III) tris (dithioacetate), chromium (I
II) Tris (dithiobenzoate), chromium (II
I) tris (2-ethyldithiohexanoate), chromium (III) tris (thiomethoxide), chromium (II
I) Tris (thioethoxide), chromium (III) tris (thiobutoxide), chromium (III) tris (thiophenoxide), chromium (IV) tetrakis (thiomethoxide), chromium (IV) tetrakis (thioethoxide), chromium (IV) tetrakis (Thiobutoxide),
Chromium (IV) tetrakis (thiophenoxide);

The chromium compound having a thiocarboxylate group, dithiocarboxylate group or thioalkoxy group is not particularly limited, and can be synthesized by a known method. For example, a chromium salt and the following general formula (3) R ¹ -SM (3) (wherein R ¹ is a hydrocarbon group having 1 to 20 carbon atoms,
Represents an acyl group having 10 to 10 or a thioacyl group having 1 to 10 carbon atoms, and M represents a metal element belonging to Group 1 or 2 of the periodic table). Chromium salts include chromium (II) fluoride, chromium (III) fluoride, chromium (II) chloride, and chromium (II) chloride.
I), chromium (II) bromide, chromium (III) bromide, chromium (II) iodide, chromium (III) iodide, among which chromium (II) chloride, chromium (II) chloride
I) is preferred. Examples of the sulfur compound include sodium thioacetate, potassium thiobenzoate, calcium thiobenzoate, sodium thiomethoxide, potassium thioethoxide, lithium thiobutoxide, lithium thiophenoxide, and the like. The reaction between the chromium salt and the sulfur compound represented by the general formula (3) is carried out by the reaction of diethyl ether, tetrahydrofuran, dioxane, 1,2-
The reaction is performed in an ether solvent such as dimethoxyethane. The reaction temperature is -78 ° C to 60 ° C, preferably -20 ° C.
The reaction is carried out at ４０40 ° C. and for a reaction time of 10 minutes to 48 hours, preferably 30 minutes to 10 hours, and the reaction is preferably carried out in a ratio of the sulfur compound to the chromium salt in the range of 1.5 to 3.5. . This reaction produces a metal salt as a by-product and precipitates in the reaction system, but the metal salt is removed by filtration. Thereafter, the ether solvent is removed under reduced pressure, and the obtained solid is an aliphatic hydrocarbon such as pentane, hexane, heptane, octane, isooctane, nonane, decane, cyclopentane, cyclohexane, methylcyclohexane, cyclooctane, and decalin. To give a chromium compound having a thiocarboxylate, dithiocarboxylate or thioalkoxy group.

Further, a complex comprising the above chromium compound and an electron acceptor can also be suitably used. The electron acceptor is not particularly limited, and examples thereof include trinitrobenzene and tetracyanoethylene. Therefore, as a complex composed of a chromium compound and an electron acceptor, for example, tricarbonyl (benzene) chromium (0) trinitrobenzene, tricarbonyl (toluene) chromium (0) trinitrobenzene, tricarbonyl (trimethylbenzene) chromium ( 0) trinitrobenzene, tricarbonyl (benzene) chromium (0) tetracyanoethylene, tricarbonyl (toluene) chromium (0) tetracyanoethylene, tricarbonyl (xylene) chromium (0) tetracyanoethylene, tricarbonyl (Trimethylbenzene) chromium (0) tetracyanoethylene and tricarbonyl (anisole) chromium (0) tetracyanoethylene.

Of these, a chromium compound containing carbon monoxide or a chromium compound having a thioalkoxy group is preferably used from the viewpoint of catalytic activity. More preferably, hexacarbonyl chromium (0), tricarbonyl (benzene) chromium (0), tricarbonyl (trimethylbenzene) chromium (0), tricarbonyl (naphthalene) chromium (0), tricarbonyl (tetralin) chromium (0) ), Tricarbonyl (cycloheptatriene) chromium (0). Further, the above chromium compounds can be used alone or in combination of two or more.

The alkyl metal compound used in the present invention is not particularly limited. For example, the following general formula (2) R _p MX _q (2) (where p is 0 <p ≦ 3) , Q is 0 ≦ q <3, and p + q is 1 to 3. M represents lithium, magnesium, zinc, boron or aluminum, and R is selected from the group consisting of alkyl groups having 1 to 10 carbon atoms. One
Wherein X represents one or more selected from the group consisting of a hydrogen atom, an alkoxy group, an aryl group, and a halogen atom).

In the above general formula (2), the number of carbon atoms is 1 to 1.
The alkyl group of 0 is not particularly limited, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a cyclohexyl group, and an octyl group.
The alkoxy group is not particularly limited,
For example, a methoxy group, an ethoxy group, a butoxy group, a phenoxy group, or the like can be given. The aryl group is not particularly limited, but includes, for example, a phenyl group. Although it does not specifically limit as a halogen atom, For example, fluorine, chlorine, bromine, or iodine is mentioned.

In the above general formula (2), M is A
l, when p and q are each 1.5, AlR _1.5 X _1.5
Becomes Although such compounds do not exist in theory, they are usually conventionally expressed as sesqui-forms of Al ₂ R ₃ X ₃ , and these compounds are also included in the present invention.

Examples of the alkyl metal compound represented by the general formula (2) include methyllithium, ethyllithium, propyllithium, n-butyllithium, s-butyllithium, t-butyllithium, diethylmagnesium, and ethylbutylmagnesium. , Ethylchloromagnesium, ethylbromomagnesium, dimethylzinc, diethylzinc, dibutylzinc, trimethylborane, triethylborane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tricyclohexyl Aluminum, dimethylethylaluminum, diethylaluminum hydride, diisobutylaluminum hydride, diethylaluminum ethoxide, diethyl Rumi bromide phenoxide, dicyclohexyl phenyl aluminum, ethyl aluminum ethoxy chloride, diethylaluminum chloride, diethylaluminum bromide, diisobutylaluminum chloride, dicyclohexyl aluminum chloride,
Examples include methylaluminum sesquichloride, ethylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum dichloride, isobutylaluminum dichloride and the like.

Of these alkyl metal compounds, alkyl aluminum compounds are preferably used in terms of availability and activity, and more preferably triethyl aluminum or triisobutyl aluminum. These alkyl metal compounds can be used alone or in combination of two or more.

The amount of the alkyl metal compound used is 0.1 to 10,000 equivalents per mole of the chromium compound.
Preferably 3-3,000 equivalents, more preferably 5-
2,000 equivalents.

In the present invention, one or more electron donors selected from the group consisting of ether compounds, ester compounds, imine compounds, isonitrile compounds, phosphine compounds, phosphine oxide compounds and phosphite compounds are used. The ether compound is not particularly limited as long as it is a compound containing an ether group, and examples thereof include diethyl ether, methyl-t-butyl ether, tetrahydrofuran, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, and triethylene glycol. Dimethyl ether, anisole, diethoxydiphenylsilane, diethoxydimethylsilane, bis (trimethylsilyl) ether, furan, 2-
Methylfuran, 3-methylfuran and the like can be mentioned. The ester compound is not particularly limited as long as it is a compound containing an ester group, and examples thereof include ethyl acetate, butyl acetate, and butyl benzoate. The isonitrile compound is not particularly limited as long as it has a C = N bond, and examples thereof include benzaldehyde ethylimine, benzaldehyde phenylimine, and benzaldehyde benzylimine. The isonitrile compound is not particularly limited as long as it is a compound containing an isonitrile group, and examples thereof include t-butyl isonitrile and cyclohexyl isonitrile. The phosphine compound is not particularly limited, but includes, for example, triphenylphosphine, tolylphosphine, tricyclohexylphosphine, trioctylphosphine, tributylphosphine, triethylphosphine, and the like. Phenyl phosphine oxide, tributyl phosphine oxide, and the like.Examples of the phosphite compound include, for example, triphenyl phosphite, tolyl phosphite, tricyclohexyl phosphite, trioctyl phosphite,
Tributyl phosphite, triethyl phosphite and the like can be mentioned.

Of these, from the viewpoint of catalytic activity and 1-hexene selectivity, ether compounds or isonitrile compounds are preferably used, and more preferably 1,2-dimethoxyethane and cyclohexylisonitrile. In addition, the above-mentioned electron donors can be used alone or in combination of two or more. The amount of the electron donor to be used is 0.01 to 100,000 equivalents, preferably 0.05 to 10,000 equivalents, more preferably 0.1 to 100 mols per 1 mol of the chromium compound.
2,000 equivalents. When the amount of the electron donor used is less than 0.01 equivalent relative to 1 mole of the chromium compound, a large amount of polyethylene is by-produced. On the other hand, the amount of chromium compound 1
If it exceeds 100,000 equivalents per mole, the catalytic activity does not increase and is not economically preferable.

The ethylene trimerization catalyst of the present invention can be prepared by bringing the above-mentioned chromium compound, alkyl metal compound and electron donor into contact with the starting materials in a solvent. Although the contacting method is not particularly limited, for example, a method of preparing a catalyst by previously contacting a chromium compound, an alkyl metal compound and an electron donor, and then contacting with ethylene to perform a trimerization reaction, ethylene as a trimerization reaction raw material A chromium compound, an alkyl metal compound and an electron donor are contacted in the presence of to prepare a catalyst, and a trimerization reaction is started simultaneously with the contact. Specifically, in the former case, (1)
(2) introducing a chromium compound into a solution containing an alkyl metal compound and an electron donor; (3) introducing an alkyl metal compound into a solution containing a chromium compound and an electron donor;
A catalyst can be prepared by a method of introducing a chromium compound and an electron donor into a solution containing an alkyl metal compound, and (4) introducing an electron donor and an alkyl metal compound into a solution containing a chromium compound. In the latter case, (1) a chromium compound, an alkyl metal compound, an electron donor, and ethylene are simultaneously and independently introduced into the reaction system, respectively. (3) introducing an alkyl metal compound and ethylene into a solution containing a chromium compound and an electron donor; (4) introducing a chromium compound and ethylene into a solution containing an alkyl metal compound and an electron donor. 5) A catalyst can be prepared by a method of introducing an alkyl metal compound, an electron donor and ethylene into a solution containing a chromium compound. The order of mixing these raw materials is not particularly limited.

The concentration of the chromium compound in the preparation of the catalyst is not particularly limited, but is usually used at a concentration of 0.001 to 100 mmol, preferably 0.01 to 10 mmol per liter of the solvent. Is done. If the catalyst concentration is lower than this, sufficient activity cannot be obtained. Conversely, if the catalyst concentration is higher than this, catalyst activity does not increase and it is not economical. As the solvent used here, for example, butane, pentane, hexane, heptane,
Aliphatic hydrocarbons such as octane, isooctane, nonane, decane, cyclopentane, cyclohexane, methylcyclohexane, cyclooctane and decalin and aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene, chlorobenzene and dichlorobenzene No. In addition, a reaction product, for example, 1-hexene can be used as a solvent. These solvents can be used alone or in combination of two or more. Here, for the purpose of controlling the chromium compound concentration at the time of preparing the catalyst, it may be concentrated or diluted as needed.

The temperature for contacting the chromium compound, the alkyl metal compound and the electron donor is -100 to 25.
0 ° C, preferably 0-200 ° C. The contact time is not particularly limited, and is 0 minute to 24 hours, preferably 0 minute to 2 hours. It is desirable that all operations during contact be performed while avoiding air and moisture. Further, it is preferable that the raw materials and the solvent are sufficiently dried.

According to the present invention, a chromium compound, an alkyl metal compound and an ether compound, an ester compound, an imine compound, an isonitrile compound, a phosphine compound, a phosphine oxide compound and a phosphite compound prepared as described above are selected. Preferably, an aluminoxane having a hydrolysis ratio of 0.7 or less is further added to the catalyst system comprising one or more electron donors to provide a catalyst for ethylene trimerization. Effects such as improvement of the catalytic activity are observed by the coexistence of an aluminoxane having a hydrolysis ratio of 0.7 or less.

The aluminoxane used in the present invention is a hydrolysis product obtained by reacting the above-mentioned alkylaluminum compound with water in a quantitative ratio within a certain range. Examples of the alkylaluminum compound include trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, and trioctylaluminum, with triisobutylaluminum being preferred. The method for hydrolyzing the alkylaluminum compound is not particularly limited, and can be synthesized by a known method. For example, (1) a method in which water is brought into contact with an alkylaluminum compound as it is or a dilute solution in an organic solvent, (2) an alkylaluminum compound and magnesium chloride · 6 hydrate, iron sulfate · 7 hydrate, copper sulfate · 5 water A method of reacting with water of crystallization of a metal salt such as a salt is employed. Specifically, Japanese Patent Application Laid-Open No. 62-26
No. 5237 and JP-A-62-148491. In addition, as described above, even if an alkyl aluminum compound is mixed with an organic solvent such as a hydrocarbon in which a very small amount of water is dissolved, the effect is sufficiently exhibited without actively performing hydrolysis.

The molar ratio of the alkylaluminum compound to water (hydrolysis ratio) at the time of the hydrolysis is 0.7 or less, preferably 0.5 or less, from the viewpoint of ease of handling and catalytic activity.
It is as follows. When the hydrolysis ratio is higher than 0.7, heterogeneous precipitates are liable to be formed, and there is a problem in reproducibility of the catalytic activity.

The aluminoxane having a hydrolysis ratio of 0.7 or less may be added at the time of the preparation of the catalyst or may be added directly to the ethylene trimerization reaction system. The amount of the aluminoxane having a hydrolysis ratio of 0.7 or less is 0.01 to 5,000 per mole of the chromium compound.
Equivalent, preferably 0.1 to 2,000 equivalents, more preferably 0.5 to 1,000 equivalents.

The trimerization reaction of ethylene is carried out using the catalyst thus prepared. In the present invention, the use amount of the chromium catalyst is not particularly limited, but usually, the chromium compound is diluted with the above-mentioned solvent, and the chromium compound is contained in an amount of 0.001 μmol to 100 mmol, preferably 0.01 μmol to 1 liter of the trimerization reaction solution. Used at a concentration of 10 mmol. If the catalyst concentration is lower than this, sufficient activity cannot be obtained. Conversely, if the catalyst concentration is higher than this, catalyst activity does not increase and it is not economical.

The temperature of the ethylene trimerization reaction in the present invention is from -100 to 250 ° C., preferably from 0 to 2 ° C.
00 ° C. The reaction pressure is not particularly limited as long as the trimerization reaction system is in an ethylene atmosphere.
3,000 kg / cm ² , preferably 0-30
It is 0 kg / cm ² . The reaction time depends on the temperature and the pressure and cannot be determined unconditionally, but is usually 5 seconds to 6 hours. Further, ethylene may be continuously supplied so as to maintain the above-mentioned pressure, or may be sealed at the above-mentioned pressure at the start of the reaction to cause a reaction. Ethylene as a raw material gas includes a gas inert to the reaction, for example, nitrogen, argon,
Helium or the like may be included. It is desirable that all operations of the trimerization reaction be performed while avoiding air and moisture.

It is preferable that ethylene is sufficiently dried.

According to the present invention, it is preferred that the catalyst comprising the chromium compound, the alkyl metal compound and the electron donor is further irradiated with light to carry out a trimerization reaction of ethylene. Effects such as a significant improvement in catalytic activity by light irradiation are recognized.

The light used in the present invention is not particularly limited, but includes, for example, ultraviolet light, visible light and infrared light, and the emission wavelength is 0.2 to 2000 nm.
Is preferable, and more preferably, light having a wavelength of 200 to 700 nm is used. Although the illuminance of light is not particularly limited, it is preferable that light is directly emitted from a light source.

Either sunlight or an artificial light source may be used as a light source. However, an artificial light source is desirable because sunlight has low illuminance, is affected by the weather, and cannot be used at night. Examples of artificial light sources include, but are not limited to, deuterium lamps, xenon lamps, tungsten lamps, incandescent lamps, halogen lamps, low-pressure mercury lamps, hollow cathode lamps, metal vapor discharge tubes, metal halide lamps, high-pressure sodium Lamps, thallium lamps, mercury-thallium lamps, mercury-lead lamps, H-type discharge tubes, xenon-mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, flash lamps, and the like.

The timing of light irradiation is not particularly limited, but the light may be irradiated to a catalyst system comprising a chromium compound, an alkyl metal compound and an electron donor, or may be directly irradiated to an ethylene trimerization reaction system. Is also good. Specifically, in the former case, (1) irradiating a solution containing a chromium compound with light, then introducing an alkyl metal compound and an electron donor and further contacting with ethylene to perform an ethylene trimerization reaction; (2) irradiating the solution containing the chromium compound and the alkyl metal compound with light, then introducing an electron donor and further contacting with ethylene to perform an ethylene trimerization reaction;
(3) The solution containing the chromium compound, the alkyl metal compound, and the electron donor can be irradiated with light by a method of irradiating the solution with light and then contacting the solution with ethylene to perform an ethylene trimerization reaction. In the latter case, (1) the ethylene trimerization reaction is performed while irradiating light in the presence of a chromium compound, an alkyl metal compound and an electron donor;
(2) Light can be irradiated by a method of performing a trimerization reaction of ethylene while further irradiating light in the presence of a catalyst comprising a chromium compound, an alkyl metal compound, and an electron donor to which light has been irradiated. Note that the light irradiation time is not particularly limited.

This reaction can be carried out in any of a batch system, a semi-continuous system and a continuous system. After the completion of the trimerization reaction, the reaction is stopped by adding a polymerization deactivator such as water, alcohol, or an aqueous solution of sodium hydroxide to the reaction solution. After the deactivated waste chromium catalyst is removed by a known deashing treatment method, for example, extraction with water or an aqueous alkali solution, the generated 1-hexene is separated from the reaction solution by a known extraction method or distillation method. In addition, polyethylene as a by-product is separated and removed at a reaction solution outlet as a residue in a known centrifugation method or distillation separation of 1-hexene.

[0039]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which are only for illustrating the outline of the present invention and the present invention is not limited to these Examples. . Example 1 In a Schlenk tube having an internal volume of 200 ml, 5.1 mg of tricarbonyl (1,3,5-trimethylbenzene) chromium (0), 3.2 ml of a 0.125 mol / l triisobutylaluminum / cyclohexane solution,
7.7 ml of a 5.2 mmol / liter cyclohexylisonitrile / cyclohexane solution and 100 ml of dried cyclohexane were added, and mixed and stirred. Under an ethylene atmosphere, light was externally irradiated for 10 minutes using an ultra-high pressure mercury lamp (500 W) manufactured by Ushio Electric.

The reaction solution was charged into a 300-ml stainless steel pressure-resistant reaction vessel equipped with a thermometer, a catalyst feed tube, and a stirrer.

After the reaction vessel was heated to 80 ° C. and the stirring speed was adjusted to 1,000 rpm, ethylene was introduced into the reaction vessel to start the ethylene trimerization reaction. Ethylene gas was blown in so that the absolute pressure in the reaction vessel became 40 kg / cm ^2. Thereafter, the introduction was continued so as to maintain the pressure, and a reaction was carried out for 5 minutes while maintaining these reaction conditions. After 5 minutes, the reaction was stopped by injecting water into the reaction vessel with nitrogen to deactivate the catalyst.

The reaction vessel was cooled to room temperature and then depressurized. The products contained in the reaction solution and the recovered gas were analyzed by gas chromatography. The solid content contained in the reaction solution was separated by filtration using filter paper, air-dried, and then dried under reduced pressure (1 mmHg, 100 ° C.), and its weight was measured. Table 1 shows the results.

Example 2 In place of cyclohexyl isonitrile, 1,2-dimethoxyethane was used in the amounts shown in Table 1 except that
The reaction was carried out in the same manner as in Example 1. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 Except that no cyclohexyl isonitrile was used
The reaction was carried out in the same manner as in Example 1. Table 1 shows the results.

[0045]

[Table 1]

[0046]

According to the present invention, a catalyst comprising a chromium compound, an alkyl metal compound and an electron donor can be easily prepared and handled. When ethylene is trimerized in the presence of this catalyst, 1-hexene useful as a raw comonomer of LLDPE can be produced with high catalytic activity and highly selectively.

[0047]

Claims (6)

[Claims] 1. A chromium compound, an alkyl metal compound and an ether compound, an ester compound, an imine compound, an isonitrile compound, a phosphine compound, a phosphine oxide compound and a phosphite compound.
An ethylene trimerization catalyst comprising at least one kind of electron donor. 2. A chromium compound represented by the following general formula (1) CrA _m (1) wherein m is an integer of 1 to 6. A is carbon monoxide, arene, alkene, alkyne, nitrogen, isonitrile, Phosphine, phosphite, sulfide, sulfoxide, thiocarboxylate group, dithiocarboxylate group, and thioalkoxy group). The ethylene trimerization catalyst according to claim 1, which is a chromium compound containing: 3. An alkyl metal compound represented by the following general formula (2): R _p MX _q (2) (where p is 0 <p ≦ 3, q is 0 ≦ q <3, and p + q is M is lithium, magnesium, zinc, boron or aluminum, and R is 1 selected from the group consisting of alkyl groups having 1 to 10 carbon atoms.
Wherein X represents one or more selected from the group consisting of a hydrogen atom, an alkoxy group, an aryl group, and a halogen atom). The ethylene trimerization catalyst according to the above. 4. The ethylene trimerization catalyst according to claim 1, wherein the ethylene trimerization catalyst further comprises an aluminoxane having a hydrolysis ratio of 0.7 or less. 5. A method for trimerizing ethylene in the presence of the catalyst for trimerizing ethylene according to any one of claims 1 to 4. 6. The method according to claim 5, wherein the ethylene trimerization catalyst is irradiated with light.